LED display screen covers and LED displays

ABSTRACT

A screen cover includes a screen cover body including an array of cover units arranged in multiple rows and multiple columns, each cover unit configured to be positioned over a respective LED lamp of an array of LED pixel units. Each cover unit has a shaped outer surface with edges, including an edge in common with an adjacent cover unit in a same row and an edge in common with an adjacent cover unit in a same column, such that the outer surfaces of the cover units along the columns and rows together form a continuous outer cover surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. patentapplication Ser. No. 15/217,492 filed on Jul. 22, 2016, which is acontinuation application of U.S. patent application Ser. No. 15,043,069filed on Feb. 12, 2016, which claims priority under 35 U.S.C. § 120 toPCT Application No. PCT/CN2015/084447 filed on Jul. 20, 2015 and ChinesePatent Application No. CN 201510080390.2 filed on Feb. 15, 2015. Thecontents of these applications are hereby incorporated by reference intheir entireties.

TECHNICAL FIELD

The disclosure relates to optical structures, particularly to LEDdisplay screen covers and LED displays.

BACKGROUND

Compared to a conventional picture tube display and a liquid crystaldisplay, a light emitting diode (abbreviated as “LED”) display possessesrelatively outstanding advantages, and one can carry out connection withany resolution ratio and can realize a wireless connection with it, andthereby satisfy the requirements for display dimensions and resolvingrate in different scenes.

A plurality of LED lamps that are provided in the LED display arearranged to form an array, and one LED lamp forms one LED pixel unit.Since light-emission area of the LED lamp is smaller than the physicalsurface area occupied by the LED pixel unit, its filling coefficient isrelatively small, and this results in clear black areas present inspaces between adjacent LED pixel units, which is manifested as aperiodic black area grid structures on the entire display. Since themajority of image acquisition devices of current photographic equipmentare charge-coupled devices (abbreviated as “CCD”), they similarly areprovided with a periodic structure, and therefore when the photographicequipment captures the LED display, and the spatial frequency whoseimage is formed by the LED display on the CCD is close to the spatialfrequency of the CCD, clear moire fringes appears, which affects thedefinition of the image. Moreover, when the filling coefficient of theLED pixel unit is relatively small, this will cause graininess and lowerthe degree of viewing comfort. At the same time, in order to guaranteethe overall brightness, the brightness of the light issued by the LEDlamp is universally rather great, but owing to the fact that thelight-emitting region is small it easily causes glare, and it is notpossible for viewers to watch it for a long time.

SUMMARY

One aspect of the invention features a screen cover including a screencover body including a plurality of cover units disposed in an array ofmultiple rows and multiple columns, each cover unit configured to bepositioned over a respective LED lamp of an array of LED pixel units ofan LED screen. A top of each cover unit forms an arched structureextending away from the LED lamp, and the arched structures of adjacentcover units are configured and joined along the columns and rows so asto provide the screen cover with a filling coefficient of more than 93%.

In some implementations, each cover unit includes a light blocking partconfigured to block off light from adjacent LED pixel units and ascattering part installed on top of the light blocking part and formingthe top of the cover unit. An outer surface of the scattering part canbe spherical. In a particular example, a spherical radius of the outersurface of the scattering part is within a range of √{square root over(2)}a/2˜0.9a, where a is a period of the LED pixel units.

In some implementations, an inner surface of each cover unit ispositioned so as to form a gap between the inner surface and an uppersurface of the LED lamp. The inner surface can be arched away from theLED lamp. The inner surface can be spherical. In a particular example,an outer surface of the scattering part is spherical, and the innersurface has a radius r determined by:

$r \geq \sqrt{R^{2} - {ab} + {\frac{1}{2}b^{2}}}$where R is a radius of the outer surface, a is a period of the LED pixelunits, and b is an edge length of the LED lamp.

In some examples, a transitional circular arc is formed between thespherical inner surface and an adjacent inner wall of the screen cover.A radius of the transitional circular arc can be within a range of0.08a-0.2a, where a is a period of the LED pixel units.

The screen cover body can have a haze of no less than 50%. The screencover can include a material having an RGB color ratio of about(1±0.2):(1±0.2):(1±0.2).

Another aspect of the invention features a screen cover has a screencover body including a plurality of cover units disposed in an array ofmultiple rows and multiple columns, each cover unit configured to bepositioned on top of a respective LED lamp of an array of LED pixelunits of an LED screen. A top of each cover unit forms an archedstructure extending away from the LED pixel lamp, the arched structuresof adjacent cover units being configured and joined along the columnsand rows such that, when placed over an illuminated LED screen, noperceptible light gaps are visible between adjacent screen pixels, asviewed through the screen cover body. The screen cover is configured tohave a filling coefficient of more than 93%.

In some implementations, each cover unit includes a light blocking partconfigured to block off light from adjacent LED pixel units and ascattering part installed on top of the light blocking part and formingthe top of the cover unit. An inner surface of the scattering part canbe a spherical surface, and a transitional circular arc can be providedbetween the inner surface and an inner wall of the light blocking part.

A further aspect of the invention features an LED display screen coverincluding a screen cover body including a plurality of cover unitsdisposed in an array of multiple rows and multiple columns, each coverunit configured to be positioned on top of a respective LED pixel lampand including a blocking part and a scattering part on top of theblocking part. An outer surface of the scattering art has an archedstructure towards a direction away from the LED pixel lamp, and thearched structures of scattering parts of adjacent cover units areconfigured joined along the columns and rows, and a material of theblocking part is selected such that the blocking part is configured toblock off light from adjacent LED pixel lamps. The arched structures ofthe adjacent cover units can be configured so as to provide the LEDdisplay screen cover with a filling coefficient of more than 93%.

In some implementations, the LED display screen cover is arranged overan array of LED pixel lamps such that each cover unit is disposed over arespective one of the LED pixel lamps, the cover units of the screencover together configured such that, with the LED pixel lampsilluminated, there is no perceptible light gap between adjacent pixelunits, as viewed through the screen cover.

A fourth aspect of the invention features an LED display including anLED display screen body of an array of LED pixel units each having arespective LED lamp and an LED display screen cover coupled to the LEDdisplay screen body and including a plurality of cover units disposed inan array of multiple rows and multiple columns, each cover unitconfigured to be positioned on top of a respective LED lamp. A number ofthe cover units in the LED display screen cover is the same as a numberof the LED lamps in the LED display screen body, and a top of each coverunit has an arched structure towards a direction away from therespective LED lamp, and the arched structures of adjacent cover unitsare configured and joined along the columns and rows so as to providethe screen cover with a filling coefficient of more than 93%.

A fifth aspect of the invention features a covered LED screen includingan array of LED pixel units arranged in multiple rows and multiplecolumns and a screen cover body with an array of LED cover unitsdisposed in multiple rows and multiple columns, each cover unitconfigured to be positioned over an LED lamp of a respective one of theLED pixel units. An outer surface of each cover unit is convex, theouter surfaces of adjacent cover units being configured and joined alongthe columns and rows, and each cover unit has an inner surface spacedfrom an outer surface of an underlying LED lamp to form a gap.

The inner surface of each cover unit can be concave. Each concave innersurface can transition to adjacent side walls of a cavity of the coverunit containing the respective LED lamp by a transitional radius.

A sixth aspect of the invention features a device for eliminating moirefringes from an LED screen and improving the filling coefficient. Thedevice includes a scattering cover and an LED screen body. Theabove-described scattering cover covers the front end of the LED screenbody, and the scattering cover is fixedly connected with the LED screenbody; and the size of the above-described scattering cover mutuallycorresponds to the size of the LED screen body; the front side of theabove-described scattering cover is formed by an array of ball topstructures, and the back side of the above-described scattering coverdefines an array of cavities corresponding to the ball top structures.The device also includes a plurality of LED pixel lamps provided on theabove-described LED screen body, each LED pixel lamp extending into acorresponding one of the cavities. The scattering cover can beconfigured to provide the LED screen with a filling coefficient of morethan 93%, when viewed through the scattering cover.

A seventh aspect of the invention features a device for eliminatingmoire fringes from an LED screen and improving the filling coefficient.The device is primarily composed of a scattering cover and an LED screenbody. The above-described scattering cover covers a front end of the LEDscreen body, and the scattering cover is fixedly connected with the LEDscreen body; and a size of the above-described scattering cover mutuallycorresponds to a size of the LED screen body; the front side of theabove-described scattering cover is provided with a plurality of balltop structures, and a back side of the above-described scattering coveris an independent groove provided with partition structures or does nothave any structures. The device also includes a plurality of LED pixellamps provided on the above-described LED screen body. Theabove-described LED pixel lamps mutually correspond to the ball topstructures, and the above-described scattering cover is provided with ahaze that is not lower than 70%.

The above-described scattering cover can include a variety of sphericalstructures: positive ball top solid bodies or shells, oval ball topsolid bodies or shells, and structures where several flat surfaces arejoined to form quasi-ball top structures or structures whose surfacesare uneven. The above-described positive ball top structures can bedetermined based on pixel dimensions of the LED pixel lamp and a haze ofthe scattering cover: if the pixel side length of an LED pixel lamp isa, then a ball top radius r of the ball top structures is (√{square rootover (2)}/2)a˜0.9a; the ball center of the ball top structures islocated at a position that has the same length difference as the radiusfrom the pixel apex angle of the upper surface of the LED pixel lamp tothe center normal line of the LED pixel lamp. The above-described balltop radius r can be selected based on a light emission position andlight emission scattering angle distribution of the LED pixel lamps anda haze of the scattering cover.

In some implementations, the above-described partition structures areindependent grooves that are produced according to a cycle of the LEDpixel lamps. The above-described grooves can be rectangular structures,and the length, width and depth of those rectangular structures can besimilar to the length, width and depth of the sealed structures of theLED pixel lamp. The bottom part of the above-described grooves can bespherical arc-shaped depression structures, and a radius of thearc-shaped depression structures can be determined by a haze of aselected material of the LED screen cover. The radius of the arc-shapeddepression structures is at a maximum not smaller than the radius r ofthe ball top structures, and the depression depth is in a range of 0 to0.5 mm.

There can be two implementation methods for connecting theabove-described scattering cover and the LED screen body: a fixedconnection with a fixing pin on the scattering body or a fixedconnection by direct bonding on the surface of the LED screen by glue onthe back side.

An eighth aspect of the invention features a method using a device foreliminating moire fringes from an LED screen and improving a fillingcoefficient described in the seventh aspect. The device for eliminatingmoire fringes from an LED screen and improving the filling coefficientdescribed in any one of the above features is used. The method includesthe following steps:

1) production of the scattering cover: a light-permeable material thatis provided with a haze of no less than 70% is employed to produce thescattering cover;

2) LED screen production;

3) installation: fixed installation employing a fixing pin: thescattering cover whose injection molding is completed in step 1) coversthe front end of the LED screen body, the fixing pins pass through thethrough holes on the printed circuit board (PCB); the fixing pins thatare passed through the back side of the PCB are heated to make themmelt, and after they cool they are remolded, that is, the scatteringcover is fixedly installed on the LED screen body; or installationemploying bonding with glue: glue is directly applied to the back sideof the scattering body or on the partition structures, and directlybonded on the surface of the LED screen body.

A ninth aspect of the invention features an LED display screen coverincluding a screen cover main body. There is provided a plurality oflamp cover units forming an array on the above-described screen covermain body, and each lamp cover unit is used for covering above arespective LED lamp. A top of the described lamp cover unit is an archstructure that faces in a direction away from the LED lamp.

In some implementations, the above-described lamp cover unit includes alight partitioning part that partitions off a space between neighboringLED lamps, and a scattering part that is installed on a top of theabove-described light partitioning part. The above-described scatteringpart is the top of the above-described lamp cover unit. The outersurface of the above-described scattering part can be a positivespherical surface. A haze of the above-described scattering part can begreater than or equal to 50%.

In some implementations, a gap used for light diffusion is provided in aspace between an inner surface of the above-described scattering partand an upper surface of the LED lamp. The inner surface of theabove-described scattering part has an arched structure facing towards adirection away from the LED lamp. The inner surface of theabove-described scattering part can be an arc surface.

In some examples, a transitional circular arc is provided between theinner surface of the scattering part corresponding to an apex angle ofthe above-described LED lamp and the inner wall of the lightpartitioning part. The radius of the above-described transitionalcircular arc can be 0.08a-0.2a, where a is the period of the LED pixelunit.

The spherical radius of the outer surface of the above-describedscattering part can be √{square root over (2)}a/2˜0.9a, where a is aperiod of the LED pixel unit. The arc surface radius r of the innersurface of the above-described scattering part can be obtained bycalculating with the following equation:

$r \geq \sqrt{R^{2} - {ab} + {\frac{1}{2}b^{2}}}$where R is the spherical radius of the outer surface of the scatteringpart, a is the period of the LED pixel unit, and b is the edge length ofthe LED lamp.

A tenth aspect of the invention features an LED display including ascreen body of an LED lamp array and the LED display screen coverdescribed in any one of the ninth aspect that is connected with theabove-described screen body. The quantity of the lamp cover units in theabove-described LED display screen cover is the same quantity as the LEDlamps.

An eleventh aspect of the invention features a screen cover including ascreen cover body including an array of cover units arranged in multiplerows and multiple columns, each cover unit configured to be positionedover a respective LED lamp of an array of LED pixel units. Each coverunit has a shaped outer surface with edges, including an edge in commonwith an adjacent cover unit in a same row and an edge in common with anadjacent cover unit in a same column, such that the outer surfaces ofthe cover units along the columns and rows together form a continuousouter cover surface.

Each cover unit can include a light blocking part configured to blockoff light from adjacent LED pixel units. Each cover unit can have aninner surface facing away from the shaped outer surface and defining arecess sized based on an upper extent of an LED housing of an underlyingLED lamp. A depth of the recess can be within a range of 0.05a ˜0.25a,where a is a period of the LED pixel units. The inner surface can be animmense extent of the cover unit. The recess can have a transitionalcircular arc between adjacent sides of the recess. The shaped outersurface can be configured such that the recess is enclosed by the shapedouter surface.

A distance between a top of the shaped outer surface and a top of therecess can be determined based on a shape of the shaped outer surface. Adistance between a top of the shaped outer surface and a top of therecess can be within a range of 0.3˜0.9a, where ‘a’ is a period of theLED pixel units.

In some cases, the shaped outer surface of the cover unit is spherical.In some cases, the shaped outer surface of the cover unit comprises anon-spherical surface including one of ellipsoid, paraboloid, and Besselsurface.

In some implementations, the shaped outer surface of the cover unitcomprises a square pyramid surface. A height defined by the squarepyramid surface can be within a range of 0.3a˜0.9a, where a is a periodof the LED pixel units. In some implementations, the shaped outersurface of the cover unit comprises a square frustum surface. A heightdefined by the square frustum surface can be within a range of0.3a˜0.9a. An edge length of a top of the square frustum surface can bewithin a range of 0.4a˜0.7a, where ‘a’ is a period of the LED pixelunits.

A twelfth aspect of the invention features a covered LED screenincluding an array of LED pixel units arranged in multiple rows andmultiple columns and a screen cover body with an array of LED coverunits disposed in multiple rows and multiple columns, each cover unitconfigured to be positioned over an LED lamp of a respective one of theLED pixel units. Each cover unit has a shaped outer surface with edges,including an edge in common with an adjacent cover unit in a same rowand an edge in common with an adjacent cover unit in a same column, suchthat the outer surfaces of the cover units along the columns and rowstogether form a continuous outer cover surface.

The shaped outer surface of the cover unit can have a lowest extent nohigher than a lighting element of an underlying LED lamp. Each LED pixelunit can be enclosed in an LED housing, and sides of the LED housing candirectly face to adjacent sides of LED housings of adjacent LED pixelunits.

In some implementations, the covered LED screen further includes aplurality of columns each protruded from an intersection of bottoms ofadjacent cover units and arranged between the respective LED pixel unitsunder the adjacent cover units. Each column can extend from the bottomsof the adjacent cover units to a printed circuit board (PCB) coupled tobottoms of the LED pixel units.

A thirteenth aspect of the invention features a screen cover including ascreen cover body including an array of cover units arranged in multiplerows and multiple columns, each cover unit configured to be positionedover a respective LED lamp of an array of LED pixel units. Each coverunit has a non-spherical shaped outer surface including one ofellipsoid, paraboloid, and Bessel surface.

A fourteenth aspect of the invention features a screen cover including ascreen cover body including an array of cover units arranged in multiplerows and multiple columns, each cover unit configured to be positionedover a respective LED lamp of an array of LED pixel units. Each coverunit has a square pyramid outer surface.

A fifteenth aspect of the invention features a screen cover including ascreen cover body including an array of cover units arranged in multiplerows and multiple columns, each cover unit configured to be positionedover a respective LED lamp of an array of LED pixel units. Each coverunit has a square frustum outer surface.

A sixteenth aspect of the invention features a covered LED screen,including: an array of LED pixel units arranged in multiple rows andmultiple columns and a screen cover body with an array of LED coverunits disposed in multiple rows and multiple columns, each cover unitconfigured to be positioned over an LED lamp of a respective one of theLED pixel units. Each LED pixel unit is enclosed in an LED housing, andsides of the LED housing directly face to adjacent sides of LED housingsof adjacent LED pixel units.

A seventeenth aspect of the invention features a covered LED screen,including: an array of LED pixel units arranged in multiple rows andmultiple columns; a screen cover body with an array of LED cover unitsdisposed in multiple rows and multiple columns, each cover unitconfigured to be positioned over an LED lamp of a respective one of theLED pixel units; and a plurality of columns each protruded from anintersection of bottoms of adjacent cover units and arranged between therespective LED pixel units under the adjacent cover units. Each columncan extend from the bottoms of the adjacent cover units to a printedcircuit board (PCB) coupled to bottoms of the LED pixel units.

Particular embodiments of the subject matter described in thisspecification can be implemented so as to realize one or more of thefollowing advantages. Owing to the facts that a plurality of lamp coverunits forming an array are installed on a screen cover main body, thateach lamp cover unit is provided above one LED pixel unit, and that atop part of each lamp cover unit is installed as an arched structurethat faces in a direction away from the LED pixel unit, the light raysemitted by an LED pixel unit can propagate from its own lamp cover unit,and the screen cover will not cause interference for adjacent pixelunits, and this guarantees a definition of an image displayed by the LEDscreen. In addition, there are no black areas present in a space betweentwo adjacent LED pixel units, and thus the screen cover will notgenerate periodic black area grid structures for the entire LED displayscreen, and makes the space between pixel units “zero distance”, whicheffectively eliminates moire fringes during screen capture; at the sametime, the screen cover improves the pixel filling coefficient, e.g.,higher than 93%, and eliminates incoherence and “graininess” of thescreen under conditions where sharpness and definition of the image areensured. The arched structures of the screen cover make light scatteringuniform. When a viewer views the LED display screen from a largeinclined angle, the brightness decay is not significant. Three primarycolors (e.g., red, green, and blue) in a single pixel can be mixedevenly in the scattering cover, which causes a softer viewing effectthan a conventional separated three primary colors on an LED lamp. Atthe same time, the scattering cover reduces the overall brightness ofthe LED screen, reduces the light contamination that might be produced,and prevents damage caused to the viewer's eyes due to excessivebrightness.

Further advantages and advantageous embodiments of the subject of theinvention can be seen from the description, the claims and the drawing.The above-mentioned features, as well as the further features listedbelow, can likewise be used independently or multiple features combinedas desired. The embodiments shown and described are not to be understoodas a conclusive list, but should rather be treated as examples toillustrate the invention. The figures in the drawing show the subject inaccordance with the invention in a highly schematic way, and are not tobe understood as being drawn to scale.

BRIEF DESCRIPTIONS OF DRAWINGS

FIG. 1 is a schematic diagram of an example assembly of an LED displayscreen cover and an LED display screen body.

FIG. 2 is a schematic diagram of a locally enlarged structure of theassembly of the LED display screen cover with the LED screen body.

FIG. 3 is a schematic diagram of a frontal view of the LED displayscreen cover.

FIG. 4 is a schematic diagram of an example structure of a front side ofthe LED display screen cover.

FIG. 5 is a schematic diagram of an example structure of a back side ofthe LED display screen cover.

FIG. 6 is a schematic diagram of an example structure of a lamp coverunit in the LED display screen cover.

FIG. 7 is a schematic diagram of another view of the lamp cover unit inthe LED display screen cover.

FIG. 8 is an example light path schematic diagram in which a scatteringglass is fitted to an LED lamp.

FIG. 9 is an example light path schematic diagram in which the LEDdisplay screen cover is fitted to an LED lamp.

FIG. 10 is a schematic diagram of a spherical center position in whichan outer surface of a scattering part of the lamp cover unit in the LEDdisplay screen cover is a positive spherical surface.

FIG. 11 is a planar view of the spherical-shaped lamp cover unit of FIG.10.

FIG. 12 is a cross-sectional view of two adjacent lamp cover units inanother example LED display screen cover.

FIG. 13 is a cross-sectional view of two adjacent lamp cover units inanother example LED display screen cover.

FIG. 14 is a light path schematic comparative diagram in which two lampcover units in two example LED display screen covers each is fitted withan LED lamp.

FIG. 15 is a schematic diagram of a spherical center position in whichan inner surface of a scattering part of the lamp cover unit in the LEDdisplay screen cover is a positive spherical surface.

FIG. 16 is a structural schematic diagram of the lamp cover unit in theLED display screen cover is fitted with an LED lamp.

FIG. 17 is a light path schematic diagram in which the LED displayscreen cover is fitted to an LED lamp.

FIG. 18 is a structural schematic diagram of an example LED displayscreen cover without light blocking parts installed with fixing pins.

FIG. 19 is a schematic diagram of glue over a back surface of an exampleLED display screen lamp without light blocking parts.

FIG. 20 is a schematic diagram of positions of glue on light blockingparts of an example LED display screen lamp.

FIG. 21 is a structural schematic diagram of an example LED displayscreen cover with light blocking parts installed with fixing pins.

FIG. 22 is a structural diagram of an example LED lamp scattering angle.

FIG. 23 is a schematic diagram showing a filling coefficient of an LEDdisplay.

FIG. 24 is a schematic diagram of an example light path in which lightfrom an LED lamp propagates into an adjacent cover unit.

FIG. 25 is a cross-sectional view of two adjacent lamp cover units in anexample LED display screen cover, where light from an LED lamp isrestricted from propagating into an adjacent cover unit.

FIG. 26A is a cross-sectional view of two adjacent lamp cover unitswithout light blocking parts in another example LED display screencover.

FIG. 26B is a cross-sectional view of two adjacent lamp cover unitswithout light blocking parts installed with fixing columns in anotherexample LED display screen cover.

FIG. 26C is a bottom view of the LED display screen cover of FIG. 26B.

FIG. 27A is a cross-sectional view of an example lamp cover unit havinga square pyramid structure in another example LED display screen cover.

FIG. 27B is a schematic diagram of a front side of the LED displayscreen cover of FIG. 27A.

FIG. 28A is a cross-sectional view of an example lamp cover unit havinga square frustum structure in another example LED display screen cover.

FIG. 28B is a schematic diagram of a front side of the LED displayscreen cover of FIG. 28A.

DETAILED DESCRIPTION

Implementations of the present disclosure are generally directed to anLED display screen cover. The LED display screen cover is installed on asurface of a screen body of an LED display screen, and can provide noperceptible light gap between adjacent LED pixels, which can effectivelyeliminate periodic black area grid structures of the LED display. Insome implementations, the LED display screen cover enables thateliminating moire fringes from the LED display screen and improving thefilling coefficient to be higher than 93% are simultaneously achieved.In addition, independence of LED pixels is ensured, mutual interferencebetween the LED pixels can be avoided, and sharpness and definition ofimages displayed by the LED display is ensured.

The filling coefficient is defined as a ratio between a light-emittingarea in a single pixel and a pixel physical surface area. For example,FIG. 22 shows an example distribution of an LED lamp light scatteringangle. FIG. 23 shows an LED display screen including nine pixel units. Asmall square with dotted lines is a single pixel physical surface, whosedimensions are 3 mm×3 mm. A square with solid lines is an LED lamppackage edge, and a circle is an LED light-emitting region, whose radiusis 0.7 mm. Thus, the filling coefficient of the LED screen is(π×0.7²/(3×3))×100%=17.1%. A relatively smaller filling coefficientresults in the screen being incoherent and incomplete when viewed from arelatively close distance, and the unevenness of the brightness causesgraininess and relatively serious glare, while the screen with a largerfilling coefficient can eliminate “graininess” and make the screensofter, and does not possess clear brightness decay when viewing with alarge inclined angle.

FIG. 1 is a schematic diagram of an assembled structure of an LEDdisplay screen body 1 of an LED display and an LED display screen cover2 according to an example embodiment. The screen body 1 of the LEDdisplay is provided with a PCB circuit board, and there is a pluralityof LED lamps 11 welded on the PCB circuit board, and each LED lamp 11forms one LED pixel unit. A plurality of LED lamps 11 form an arraystructure. The screen body 1 is connected with the LED display screencover 2, and the LED display screen cover 2 includes a screen cover mainbody and a plurality of lamp cover units 21 forming an array of multiplerows and multiple columns provided on the screen cover main body. Eachlamp cover unit 21 is positioned on top of about a respective LED pixellamp 11 and used for covering the LED pixel lamp 11. The screen covermain body can be bonded together with the screen body 1 (e.g., by gluebonding), connected by employing a bolt, connected by clamping with afastener, or connected with pins.

FIG. 2 is a schematic diagram of the locally enlarged structure of theassembly of the LED display screen cover 2 with the LED screen body 1.The screen cover 2 includes a plurality of cover units 21 and ispositioned on top of the LED screen body 1. FIG. 3 is a schematicdiagram of a frontal view of the LED display screen cover 2. FIG. 4 is aschematic diagram of an example structure of a front side of the LEDdisplay screen cover 2. The cover units 21 are joined together along therows and columns to form a two-dimensional screen cover 2. FIG. 5 is aschematic diagram of an example structure of a back side of the LEDdisplay screen cover 2. As discussed below, the screen cover 2 includesa light blocking part 211. One or more fixing pins 215 can be set up onthe surface of the back side for fixing the screen cover 2 and thescreen body 1 with the PCB circuit board.

Each lamp cover unit 21 can have a same structure. FIG. 6 is a schematicdiagram of an example structure of the lamp cover unit 21 in the LEDdisplay screen cover 2, and FIG. 7 is a schematic diagram of anotherangle of the lamp cover unit 21 in the LED display screen cover 2. Asshown in FIGS. 6 and 7, a top part of the lamp cover unit 21 has anarched structure facing away from the LED lamp 11.

The structure of the lamp cover unit 21 can be implemented in differentways. In some implementations, as FIGS. 6 and 7 show, the lamp coverunit 21 includes a light blocking part 211 that blocks off light fromadjacent LED lamps 11 and a scattering part 212 installed on the toppart of the light blocking part 211. The outer surface of the scatteringpart 212 is an arch facing towards a direction away from the LED lamp11. The light blocking part 211 and the scattering part 212 can beformed integrally or be bonded together.

In some examples, a sealed (e.g., packaged or assembled) structure ofthe LED lamp 11 is cuboid, and an inner wall of the light blocking part211 surrounds the cuboid structure and accommodates the LED lamp 11. Inorder to adapt to the structure of the adjacent LED lamps 11, outerwalls on the four side surfaces of the light blocking part 211 can beplanes. Two adjacent lamp cover units 21 can be joined by putting theouter walls of the light blocking parts 211 together. Alternatively, thelight blocking parts 211 of two adjacent lamp cover units 21 can be anintegral structure.

As for the arched structure in which the scattering part 212 faces in adirection away from the LED lamp 11, an intersection line of twoadjacent scattering parts 212 is coplanar with the outer wall of thelight blocking part 211, and said plane is perpendicular to the surfaceof the LED lamp 11 provided in the screen body 1. In a situation wherethe light blocking part 211 in two adjacent lamp cover units 21 is anintegral structure, the intersection line of the two adjacent scatteringparts 212 is located between the light blocking part 211.

FIG. 8 is a light path schematic diagram in which a scattering glass isfitted to an LED lamp. A piece of scattering glass is provided as acover on two LED lamps 11. The scattering glass has a back plane thatfaces towards an inner surface of the LED lamps 11 and a front planethat faces away from an outer surface of the LED lamps. Light-emittingpoints of the two LED lamps 11 are O1 and O2, respectively. In lightrays emitted from the light-emitting point O1, the light rays O1E, O1Fand O1G that are emitted towards the center of the two LED lamps 11 onthe left and right respectively coincide on the projection points E, Fand G on the scattering glass with the light rays O2E, O2F and O2G thatare emitted from light-emitting point O2. Therefore, the two light raysthat are respectively located at each projection point positioninterfere with each other, and this results in an image at theprojection point being relatively indistinct, which in turn results inthe edges of the LED pixel units being relatively indistinct. Thescattering glass includes a scattering film (or layer) on its surface tocause light scattering, however, due to restrictions of scattering filmtechnology, the scattering angle of the scattering glass is not large,and the screen brightness rapidly decays along with an increase of theviewing angle.

FIG. 9 is a light path schematic diagram in which the LED display screencover 2 is fitted to an LED lamp 11. The lamp cover unit 21 is providedabove the LED lamp 11, and the light rays emitted by the LED lamp 11exhibit a dispersed state and are emitted towards the lamp cover unit21. FIG. 9 shows two left and right adjacent LED lamps 11, and one lampcover unit 21 is provided as a cover above each LED lamp 11. Thelight-emitting points of the two left and right LED lamps are O1 and O2,respectively. Taking light-emitting point O1 as an example, among lightrays emitted by O1, light ray O1A is irradiated on an intersection lineof the scattering part 212 of the two lamp cover units 21, theprojection point on the intersection line is A, and it is only when thelight O1A further passes through the AB segment that reaches point B onthe scattering part 212 of the right lamp cover unit 21. The lightbrightness (or intensity) is largely consumed in the AB segment lightpath, and consequently becomes extremely weak even if the light ray O1Acan enter the right lamp cover unit 21. Using O1A as the boundary line,if the dispersion angle in the light rays emitted by the light-emittingpoint O1 is relatively large and even if the light rays beneath O1A canenter the right lamp cover unit 21, their brightness is also extremelyweak. On the other hand, if the dispersion angle is relatively small andthe light rays above O1A (e.g., O1C and O1D) are all incident on thescattering part 212 of their own lamp cover unit 21 and propagate out,they will not enter the right lamp cover unit 21. Therefore, the lightrays emitted by the right LED lamp 21 will propagate from their own lampcover unit 21, and will not cause interference towards the adjacent LEDpixel units. Moreover, no black areas are present in the space betweentwo adjacent LED pixel units, which improves the pixel fillingcoefficient and makes the space between LED pixels a “zero distance” andin turn makes the LED screen softer and clearer.

Referring back to FIG. 9, for the above-described scattering part 212,its inner surface is a surface facing towards the LED lamp 11, and theouter surface is a surface facing away from the LED lamp 11. The outersurface of the above-described scattering part 212 has an archedstructure facing towards in a direction away from the LED lamp 11.

The arched structure of the scattering part 212 can be implemented indifferent ways. In some implementations, the outer surface of thescattering part 212 is a spherical surface, e.g., a positive sphericalsurface or an ellipsoid. In some implementations, the outer surface isan arc surface, e.g., a hyperboloid or a paraboloid, or several planesare joined to form the arched structure. The scattering part 212 can bea solid body structure or a shell-shaped structure. In someimplementations, the scattering part 212 includes a positive ball topsolid body or shell, oval ball top solid body or shell, or a structurewhere several flat surfaces are joined to form a quasi-ball topstructure or an uneven structure.

For purpose of illustration, the present embodiment uses a scatteringpart 212 whose outer surface is a positive spherical surface as shown inFIGS. 1-7 and 9. To provide a more detailed explanation of the structureof the lamp cover unit 21, a person skilled in this field can apply thetechnical scheme provided in the present embodiment to a lamp cover unitwith another shape, or make modifications and apply them to a lamp coverunit with another shape.

In some implementations, the scattering part 212 has a positivespherical surface, and its spherical surface radius R can be determinedbased on dimensions of the LED pixel unit. If an LED lamp 11 is a squarestructure when viewed from above and a period of the LED pixel unit isa, the spherical surface radius R can be √{square root over (2)}a/2 to0.9a. The period of the LED pixel unit is defined as a distance betweenlight-emitting points of two adjacent LED lamps 11, e.g., a distancebetween O1 and O2 in FIG. 9. When a scattering part 212 with a positivespherical surface is employed, its outer surface can be continuous,round, and smooth, which can not only avoid light ray interferencebetween adjacent pixel units but also improve the filling coefficient.For the structure shown in FIG. 9, since the top surface of the lampcover unit 21 is a positive spherical surface, the light rays aredispersed in all directions after they propagate from the light coverunit 21, and consequently the brightness decay under conditions of arelatively large viewing angle is not significant.

FIG. 10 is a schematic diagram of a spherical center position in whichthe outer surface of the lamp cover unit scattering part in the LEDdisplay screen cover is a positive spherical surface. FIG. 11 is aplanar view of the spherical-shaped lamp cover unit of FIG. 10. Point Nand point P are intersection points of the intersection line of twoadjacent lamp cover units 21 and two relative edges in the lightblocking part 211. A line segment MP is parallel to the PCB circuitboard and also parallel to the bottom surface of the light blocking part211. A line segment NY is a distance from point N to the bottom surfaceof the light blocking part 211, and it is also the height of the lightblocking part 211. The length L_(NY) of line segment NY can be0.45a-0.7a, and a is the period of the LED pixel unit. The sphericalcenter M of the outer surface of the scattering part 212 is within theplane of the NP line segment and the location of the projection of theNP segment on the PCB circuit board, and is located on the centralperpendicular line segment TX of the NP segment (i.e., the centralnormal line of the LED pixel unit). On the central perpendicular linesegment TX, the length of line segment TX is equal to the length L_(NY)of the line segment NY, that is, 0.45a-0.7a, and the length L_(MT) ofline segment MT is:

$L_{MT} = \sqrt{R^{2} - {\frac{1}{2}a^{2}}}$where R is the spherical surface radius of the outer surface of thescattering part 212, and a is the period of the LED pixel unit. Adistance between the spherical center M of the outer surface of thescattering part 212 and the bottom surface of the light blocking part211 is equal to the length L_(MX) of the line segment MX, which is thedifference between the length of the above-described line segment TX andthe length of line segment MT.

In addition to possessing the above-described functions and advantages,the scattering part 212 also possesses the function of carrying outscattering for the light rays emitting from the LED lamp 11 to make thelight rays that emit from the scattering point no longer irritating tothe eye, and the extent of its scattering is called the haze. In someimplementations, a scattering film is pasted on the outer surface of thescattering part 212. The scattering film can cause the scattering part212 to have a haze larger than 50%, preferably larger than 70%. In someimplementations, a material possessing a fixed haze is used to make thescattering part 212. The material can cause the scattering part 212 tohave a haze larger than 50%, preferably larger than 70%.

The above-described light blocking part 211 can also have a fixed haze,and if the light blocking part 211 and scattering part 2212 integrallyconstitute the lamp cover unit 21, it is possible to use a material witha fixed haze to make the entire lamp cover unit 21. The light rayspropagate from the lamp cover unit 21 and will be dispersed in everydirection, and the light source seen by the naked eye is the entire lampcover unit 21 with light emerging, and in this way the point lightsource is expanded to the surface of the entire lamp cover unit 21. Whenviewed from the outside of the LED display screen cover, the entire LEDdisplay screen cover is lit up, and one cannot see the shape of the LEDlamps 11, and this can eliminate the graininess of the LED displayscreen cover.

Further, if the lamp cover unit 21 is made by employing materials with afixed haze, it is specifically possible to make it by using materialswhose haze is larger than 50%, and preferably larger than 70%, whichpossesses relatively good visual effects.

In some implementations, the above-described spherical surface radius ofthe outer surface of the scattering part of the lamp cover unit 21 isset based on the light emission position of the LED lamp 11, thedistribution of the light scattering angle of the LED lamp 11, and thehaze of the lamp cover unit 21.

Further improvements of the structure of the lamp cover unit 21 can becarried out. In some implementations, when the scattering part 212 inthe lamp cover unit 21 is a real solid structure, it is possible toprovide a groove that faces in the direction away from the LED lamp 11from the inner surface of the scattering part 212, and thereby provide agap used for light dispersion between the inner surface of thescattering part 212 and the upper surface of the LED lamp 11. The crosssection of the groove can be rectangular, round, oval, etc., and saidcross section is the surface on which the LED lamp 11 is providedparallel to the screen body 1.

FIG. 12 is a cross-sectional view of two adjacent lamp cover units inthe LED display screen cover. A gap that is used for light dispersion isprovided in the space between the inner surface of the scattering part212 and the upper surface of the LED lamp 11. Specifically, a groove 22that is rectangular in cross section is provided in the space betweenthe upper surface of the LED lamp 11 and the inner surface of thescattering part 212, and the groove 22 forms a gap in the space betweenthe inner surface of the scattering part 212 and the upper surface ofthe LED lamp 11. The length and breadth of the groove 22 matches thedimensions of the LED lamp 11, and the depth HI of the groove 22 can bedetermined based on the sealing dimensions of the LED lamp 11, thecircumstances of the welding spots and light angle distributioncharacteristics, and the optical characteristics of the materials usedto make the scattering part 212. The depth HI of the groove 22 can be0.35b to 0.8b, wherein b is the side length of the LED lamp 11. In aparticular example, the depth HI is within a range of 0 to 0.5 mm.

The groove 22 provides a space for placing the LED lamp 11, and thegroove 22 can also be used to carry out dispersion and mixing threeprimary color light rays (e.g., red, green, blue) emitted by the LEDlamp 11 before they enter the lamp cover unit 21. For example, the LEDlamp 11 includes three LED emitters for emitting red, green, blue colorlight, respectively.

In FIG. 12, the scattering part 212 and light blocking part 211 are anintegral structure, and the light blocking part 211 serves as the sidewall of the groove 22 and can be used for fixing on the above-describedscreen body 1 or stuck in the space between adjacent LED lamps 11. Thelight blocking part 211 plays a role of supporting the scattering part212, and it can also play the role of position fixing and thereby makeone lamp cover unit correspond to one LED lamp 11 for which it isprovided as a cover and make the entire screen cover have no movement inrelative to the LED lamps 11.

FIG. 13 is a cross-sectional view of two adjacent lamp cover units inthe LED display screen cover provided in another embodiment. As shown inFIG. 13, a first column 23 is provided in the space between the sidewall of the groove 22 (or otherwise the light blocking part 211) and thesurface of the PCB circuit board 12. The first column 23 is located inthe space between two adjacent LED lamps 11, and is used to support thelight blocking part 211. The first column 23 can be bonded, bolted orconnected with pins on the PCB circuit board 12 to realize the fixing,or through hole created inside the PCB board 12. A second column 24 canbe provided inside the through hole, and can be bonded or welded insidethe through hole of the PCB board. The second column 24 can be used tosupport the first column 23. Alternatively, the first column 23 andsecond column 24 can be an integral structure. In FIG. 13, the firstcolumn 23 can be a cylinder or cube, and the second column 24 can be acylinder or cube. Taking a cylinder as an example, the diameter of thefirst column 23 is relatively rough, whereas the diameter of the secondcolumn 24 is relatively fine and the length is relatively long, and thecontact surface with the PCB circuit board 12 is relatively large, andit is used for fixing on the PCB circuit board 12.

On the basis of the above-described technical scheme, another embodimentcan be carried out for improvements of the structure of the lamp coverunit 21: the inner surface of the scattering part 212 faces towards thearch in a direction facing away from the LED lamp 11. That is, the innersurface of the scattering part 212 is an arch-like structure or archedstructure, and said structure can be a spherical surface, e.g., apositive spherical surface or an ellipsoid; alternatively it is an arcsurface, e.g., a hyperboloid, a paraboloid, etc.; or several planes arejoined to form the structure of an arch.

FIG. 14 is a light path schematic comparative diagram in which two lampcover units in the LED display screen cover provided in anotherembodiment each are fitted with an LED lamp. The inner surface of thescattering part 212 in the right lamp cover unit 21 is an arched or arcsurface, while the inner surface of the scattering part 212 in the leftlamp cover unit 21 is not an arched structure but rather a plane. Forthe left structure, the light rays emitted by the LED lamp enter theinside of the scattering part 212 and refraction occurs, and the angleof the refraction is relatively small; the light rays converge towardsthe center of the scattering part 212, and this may be unfavorable fordispersion of the light rays in all directions, and furthermore this mayresult in a black side formed on the boundary of the LED pixel unit.

On the other hand, the light rays emitted by the right LED lamp 11 enterthe inside of the scattering part 212 and refraction occurs, but owingto the act that the incidence surface is an arched or arc surface, theangle of the refraction is relatively large, the light rays aredispersed in all directions and the occurrence of a black side on theboundary of the LED pixel unit can be avoided. In the lamp cover unit 21displayed in FIG. 7, the inner surface of the scattering part 212 is apositive spherical surface, and the spherical surface radius r of theinner surface of said scattering part 212 can be obtained by calculatingwith the following equation:

$r \geq \sqrt{R^{2} - {ab} + {\frac{1}{2}b^{2}}}$where R is a spherical surface radius of the outer surface of thescattering part 212, a is the period of the LED pixel unit, and b is theside length of the LED lamp 11.

In some implementations, the spherical surface radius r of the innersurface of the scattering part is determined by a haze of a material ofthe scattering part, and a maximum of the radius r is not smaller thanthe spherical surface radius R of the outer surface of the scatteringpart.

In addition, for the spherical center position of the inner surface ofthe scattering part 212, one can refer to FIG. 15. FIG. 15 is aschematic diagram of the spherical center position in which the innersurface of the lamp cover unit scattering part 212 in the LED displayscreen cover is a positive spherical surface. FIG. 15 shows aperspective view of the lamp cover unit 21, where the boundary of theinside of the lamp cover unit is indicated by the dot-dash line. Point Vand point W are respectively the intersection points between theintersection line between the inner surface of the scattering part 212and the inner surface of the light blocking part 211 and the tworelative edges in the light blocking part 211. The line segment VW isparallel to the PCB circuit board 12, and is also parallel to the bottomsurface light blocking part 211. The distance between point W and thebottom surface of the light blocking part 211 (that is, the distanceLZ_(Q) between the midpoint of the line segment VW and the bottomsurface of the light blocking part 211) can be determined based on theheight of the LED lamp 11 and the depth HI of the groove 22. Thespherical center U of the inner surface of the scattering part 212 islocated within the plane of line segment VW and the projection locationof line VW on the PCB circuit board 12, and is also located on thecentral perpendicular line segment ZQ of the VA segment (that is, thecentral normal line of the LED pixel unit). On the central perpendicularline segment ZQ, the length L_(UZ) of line segment UZ is:

$L_{UZ} = \sqrt{R^{2} - {\frac{1}{4}c^{2}}}$where R is spherical surface radius of the outer surface of thescattering part 212 and c is the side length of the groove 22. The sidelength of the groove 22 can be a little bit larger than the side lengthof the LED lamp 11. The distance L_(UQ) between the spherical center Uof the inner surface of the scattering part 212 and the bottom surfaceof the light blocking part 211 is the difference between the distanceL_(ZQ) between the midpoint A and the bottom surface of the lightblocking part 211 and the length L_(UZ) of the line segment UZ, that is,L_(UQ)=L_(ZQ)−L_(UZ).

On the basis of the above-described technical scheme, furtherimprovements can be made for the lamp cover unit 21. In someimplementations, a transition circular arc is provided in the spacebetween a corner of the inner surface of the scattering part 212 and theinner wall of the light blocking part 211. The cover unit 21 can havethe transition circular arcs on all four connection corners between theinner surface of the scattering part 212 and the inner wall of the lightblocking part 211.

FIG. 16 is a structural schematic diagram of the lamp cover unit in theLED display screen cover provided in another embodiment is fitted withan LED lamp, and FIG. 17 is a light path schematic diagram in which theLED display screen cover is fitted to an LED lamp. In order to undertakea more detailed description of the above-described technical scheme, theview angle of FIG. 17 is a cross-sectional view that is opened along thediagonal of the LED lamp, and what is displayed on the right side ofFIG. 17 is that a transitional arc 214 is provided in the space betweenthe corner of the inner surface of the scattering part 212 and the innerwall of the light blocking part 211, and what is displayed on the leftside thereof is that no such transitional arc 214 has been provided inthe space between the corner of the inner surface of the scattering part212 facing the LED lamp and the inner wall of the light blocking part211, and this is just for the sake of comparison.

As FIG. 17 shows, no transitional circular arc is set up between theinner surface of the scattering part 212 on the left side and the innerwall of the light blocking part 211. J is the conjunction point of theinner surface of the scattering part 212 and the inner wall of the lightblocking part 211. Some of the light from the LED lamp 11 is projectedto the point J where it is reflected toward JK and JL. So a black areaappears at the conjunction point of the outer surface of the scatteringpart 212 and the outer wall of the light blocking part 211. That is, ablack area appears, e.g., between K and L, around the top part of theLED lamp.

A transitional circular arc is set up between the inner surface of thescattering part 212 on the right side and the inner wall of the lightblocking part 211. The light from the LED lamp 11 is refracted by thetransitional circular arc to evenly reach the conjunction point of theouter surface of the scattering part 212 and the outer wall of the lightblocking part 211. No black area appears at the conjunction point. Thatis, no black area appears around the top corner of the LED lamp. In thesame way, the light from LED lamp 11 evenly reaches the whole surface ofthe scattering part 212 and completely gets rid of the black area on thetop corner of the LED pixel unit. A radius of the transitional circulararc can be determined in accordance with the sizes of the scatteringpart 212, the light blocking part 211, and the LED lamp. In someexamples, the radius of the transitional circular arc is from 0.08a to0.2a, where a is the period of LED pixel unit.

The color of the LED display screen cover itself is an importantspecification because it can shift the overall color of images displayedby the LED display screen toward the color of the LED display screencover. For example, if the color of the LED display screen cover is red,then the overall color of images is shifted toward red. In someimplementations, to avoid the impact of the color of the LED displayscreen cover itself on the overall color of images, dark-coloredmaterials are selected for manufacturing the LED display screen cover.In some examples, materials of a grayscale value from 0 to 125 areselected, and the RGB (red:green:blue) ratio is about(1±0.2):(1±0.2):(1±0.2). In a particular example, the ratio is 1:1:1.

The RGB ratio can be determined based on color cards that are commonlyused in this industry. For example, Ral Plastics color card provides thefollowing colors: RAl 1000-P, RAl 1011-P, RAl 1020-P, RAl 4007-P, RAl5003-P, RAl 5011-P, RAl 6003-P, RAl 6009-P, RAl 7001-P, RAl 7004-P, RAl7011-P, RAl 7012-P, RAl 7015-P, RAl 7016-P, RAl 7021-P, RAl 7024-P, RAl7031-P, RAl 7037-P, RAl 8014-P, RAl 8017-P, RAl 8025-P, and RAl 9011-P.The above-referenced colors are not fixed. Other colors can be alsoselected.

The LED display screen cover used for the LED display screen includes anarray of lamp cover units over the LED display screen. Each lamp coverunit is placed above a respective LED lamp, and the top of the lampcover unit is an arched structure facing away from the LED lamp. In sucha way, light from each LED lamp can only go out through the respectivelamp cover unit above, and won't affect adjacent LED pixel units. Alsothe arched structures of the lamp cover units can uniformly diffuse orscatter the light emitted by the LED lamps to a size of the physicalarea occupied by the LED pixel units, and the filling coefficient can begreater than 93%. This mechanism makes the images displayed by the LEDdisplay clearer. No perceptible black area appears between two adjacentLED pixel units. Therefore, periodic black area grid structures will beeliminated from the entire LED display screen, which makes “no gap”between two adjacent LED pixel units or very small gaps such that it isimpossible to form interference fringes. Images become softer and arefree from a grainy look.

FIG. 18 is a structural illustration of another implementation of theLED screen cover. The lamp cover unit 21 has the above referencedscattering part 212, but no light blocking part 211. The top of the lampcover unit 21 is a structure that arches away from the LED lamp. Thedetails of how to design the arched structure are described above. AsFIG. 18 shows, the lamp cover unit 21 does not have a light blockingpart 211, so the lamp cover units 21 and the PCB circuit board can bescrewed or pinned together, e.g., by at least one fixing pin 215. Thelamp cover units 21 and the PCB circuit board can be also gluedtogether. As shown in FIG. 19, a fixed connection between them isachieved by direct bonding on the surface of the LED screen by glue onthe back side of the lamp cover units 21.

FIG. 1 shows another implementation of an LED display screen. Thisimplementation includes the LED display screen body 1 that has an arrayof LED pixel lamps and the LED display screen cover 2 that includes aplurality of lamp cover units 21 and is connected to the screen body 1.The number of the lamp cover units 21 and the number of the LED lamps 11can be the same. The size of the LED display screen cover 2 correspondsto the size of the LED screen body 1. The plurality of lamp cover units21 of the LED display screen cover can be integrally formed into a wholepiece. In some examples, if an LED display screen has 192×192 LED lampsand if an LED display screen cover has 32×16 cover units, then 6×12pieces of LED display screen covers are needed to cover the LED displayscreen.

There are multiple methods to connect the LED display screen cover 2 andscreen body 1.

One of the methods is to glue them together. FIG. 20 shows a schematicdiagram of places for applying glue for the implementations method. Glueis applied to an end of the light blocking part 211 in the LED displayscreen cover so that it can be connected to the PCB circuit board of theLED screen body 1 between two adjacent LED lamps. Each lamp cover unitis placed above a respective LED lamp.

Another implementations method is to pin them together. FIG. 21 showsplaces for applying pins. At least one fixing pin 215 is set up on thesurface of the screen cover that faces the LED lamps. Correspondingly,the PCB circuit board of the screen body 1 has a pin hole. The LEDdisplay screen cover 2 and screen body 1 are connected when the fixingpin 215 is inserted into the pin hole of the PCB circuit board.

Implementations of the present disclosure also provides methods ofmanufacturing LED displays or LED display screens with the followingsteps:

1) a light-permeable material having a haze greater than 50% (or greaterthan 70%) is selected to manufacture the LED display screen cover.Plastic injection technology can be applied.

2) the LED display screen body is manufactured. An array of LED pixellamps is arranged on a substrate (e.g., PCB circuit board) to form theLED display screen body. In some examples, each LED pixel lamp is apackaged lamp including three emitters emitting three primary colors(red, green and blue). In some examples, the LED display screen body isformed by directly placing three emitters on the center of each LEDpixel on the substrate without packaging (or assembling). The LEDdisplay screen cover can be configured to cover the three emitters foreach LED pixel.

3) the LED display screen cover and the LED display screen body areinstalled together by at least one of the methods:

I) pinning them together. The LED display screen cover manufactured instep 1) is placed in front of the LED display screen body manufacturedin step 2). Fixing pin 215 is inserted into the pin hole on the PCBcircuit board. Heat is used to melt the pin end sticking out on the backside of the PCB circuit board. After the pin end cools off, the screencover and the screen body are fixed together, or

II) gluing them together. Glue can be directly to the back side or thelight blocking part of the LED display screen cover. Then the LEDdisplay screen cover is pressed on the surface of the LED display screenbody.

In a particular example, for P2.5 LED display screen body, its pixelperiod is 2.5 mm. The package size of the LED display screen body is 2mm×2 mm×0.7 mm. The thickness of the PCB circuit board is 2 mm. Theresolution of the LED display screen body is 80×32. That is, there are80×32 LED lamps on a PCB circuit board. The manufacturing of the LEDdisplay screen can include the following steps:

Step 1: production of the LED display screen cover. Polycarbonate (PC)injection molding is used, and one LED display screen cover is made into16×16, that is, it can cover 16×16 LED pixel lamps. The polycarbonatematerial haze is 95%. When a black master batch with a thickness smallerthan 1 mm is added, the light permeability of the material becomes 50%.The LED display screen cover period is 2.5 mm; the spherical surfaceradius of the spherical surface scattering part in the lamp cover unitis designed to be 2.06 mm; the groove 22 has a length and a breadth thatare both 2 mm+0.1 mm (positive allowance), and a depth that is 0.7mm+0.05 mm (positive allowance); for the groove bottom, based on thecircumstances, it is possible to make a spherical arc-shaped depressionstructure (that is, a structure in which the inner surface inside theabove-described scattering part 212 is an arc surface). In the presentembodiment the arc surface radius is 3 mm and the arc surface depth is0.2 mm; the fixing pin is a cylinder with dimensions of Φ 0.7 mm-0.5 mm(negative allowance)×2.3 mm. One LED screen body requires 5×2 LED screencovers.

Step 2: production of the LED screen body. It can be produced accordingto general LED screen production methods. To install 5×2 scatteringcovers on the LED screen body, through holes Φ 0.7 mm+0.5 mm (positiveallowance) are created respectively in the corresponding positions.

Step 3: installation. The injection molded LED display screen covers arecovered on the front end of the LED screen body according to a mode of5×2, and the fixing pins pass through the through holes on the printedcircuit board (PCB). The fixing pins that are passed through the backside of the PCB are heated to make them melt, and after they cool theyare remolded such that the scattering cover is fixedly installed on theLED screen body.

In such a way, the production of one LED screen body with LED displayscreen covers is completed. After that, several LED screen bodiesinstalled with LED display screen covers may be connected according toinstallation and production process of ordinary LED large screens toachieve a larger LED display screen.

Alternatively, in the above-described step 3, the LED display screencovers can be fixed to the LED screen body by applying glue to the backside of the LED display screen covers. After the glue has been appliedto the entire flat surface of the back side of the LED display screencovers, the LED display screen covers may be directly covered on thesurface of the LED screen body and bonding may be done.

FIG. 24 is a schematic diagram of an example light path in which lightfrom an LED lamp 244 in an LED pixel unit propagates into an adjacentcover unit. The LED lamp 244 includes LED lighting elements 245, e.g.,red LED, green LED, and blue LED, positioned on an LED base 247, whichcan be further arranged on a PCB board. The lighting elements 245 can beelectrically coupled to drive circuits on the PCB board and emit lightwhen driven by the drive circuits. In some implementations, the lightingelements 245 are packaged in an LED housing 246, e.g., a transparentcover.

The cover unit 240 is configured to be positioned over the respectiveunderlying LED lamp 244. The cover unit 240 can be similar to the coverunit 21 of FIGS. 1, 2, and 4. The cover unit 240 includes a scatteringpart 241. The scattering part 241 can be similar to the scattering part212 of FIG. 7, and can have a spherical outer surface. The sphericalouter surface of the scattering part 241 has edges including an edge incommon with an adjacent cover unit in a same row and an edge in commonwith an adjacent cover unit in a same column. Outer surfaces of coverunits arranged in the columns and the rows can together form acontinuous outer cover surface.

The scattering part 241 has an inner surface facing away from thespherical outer surface and defining a recess 243 sized based on the LEDhousing 246 of the underlying LED lamp 244. The recess 243 can have atransitional circular arc between adjacent sides of the recess 243. Thetransitional circular arc can be similar to the transitional circulararc 214 of FIG. 17.

The cover unit 240 includes a light blocking part 242 configured toblock off light from an adjacent LED lamp and/or light from the LED lamp244 to the adjacent cover unit. The light blocking part 242 can besimilar to the light blocking part 211 of FIG. 7.

In some cases, due to the packaging of the LED light elements 245, theLED light elements 245 can emit light from sides, as illustrated in FIG.24. In some cases, the light blocking part 242 can scatter light. Forexample, the light blocking part 242 can be made of a material same asthat of the scattering part 214. When the cover unit 240 is positionedabove the LED lamp 244, the light emitted from the sides of the LEDlight elements 245 can be scattered by the light blocking part 242 tothe adjacent cover unit, e.g., to a top of the scattering part of theadjacent cover unit, as illustrated in FIG. 24, which can cause lightinterference between adjacent LED pixel units.

FIG. 25 is a cross-sectional view of two adjacent lamp cover units 250in an example LED display screen cover. By changing a shape of an outersurface of the lamp cover unit 250, light from an LED lamp 254 in an LEDpixel unit can be restricted or prevented from propagating into anadjacent cover unit. The LED lamp 254 can be similar to the LED lamp 244of FIG. 24, and includes

LED light elements 255 positioned on an LED base 257 and packaged by anLED housing 256. The cover unit 250 is configured to be positioned overthe LED lamp 254. The cover unit 250 also includes a scattering part 251and a blocking part 252. An inner surface of the scattering part 251defines a recess 253 sized based on an upper extent of the LED housing256 of the underlying LED lamp 254.

Different from the cover unit 240 of FIG. 24, the cover unit 250 has ashaped outer surface that is non-spherical. That is, the scattering part251 is different from the scattering part 241 of FIG. 24 and has anon-spherical shaped outer surface. The non-spherical shaped outersurface can include one of ellipsoid, paraboloid, and Bessel surface.

A top (or a highest extent) of the scattering part 251 can be higherthan that of the scattering part 241, and a bottom (or a lowest extent)of the scattering part 251 can be lower than that of the scattering part241, such that the recess 253 is enclosed, at least partially, by thenon-spherical shaped outer surface of the scattering part 251. Thenon-spherical shaped outer surface of the scattering part 251 has alowest extent no higher than a lighting element 255 of the underlyingLED lamp 254. In some cases, a distance between the top of thenon-spherical shaped outer surface of the scattering part 251 and a topof the recess 253 is within a range of 0.3˜0.9a, where a is a period ofthe LED pixel units. An optimal value of the distance can be determinedbased on a shape of the outer surface of the scattering part 251 and/ora type of the LED lamp 254.

As noted above in FIG. 24, the light blocking part 242 of the cover unit240 can scatter light emitted from sides of the LED lamp 244 to theadjacent cover unit, which can cause light interference between theadjacent LED pixel units. However, if a cover unit has no light blockingpart, the light interference between the adjacent LED pixel units can bereduced or eliminated.

As an example, FIG. 26A shows a cross-sectional view of two adjacentlamp cover units 260 without light blocking parts in another example LEDdisplay screen cover. The cover unit 260 only includes a lightscattering part 261. An LED lamp 264 in an LED pixel unit includes LEDlighting elements 265 positioned on an LED base 267 and packaged by anLED housing 266. The LED base 267 can be fixed on top of a PCB board.Without light blocking parts of the cover units 260, sides of the LEDhousing 266 of the LED lamp 264 directly face to adjacent side of an LEDhousing of an adjacent LED lamp.

As illustrated in FIG. 26A, without a light blocking part, a majorityportion of light emitted from a side of the LED lamp 264 (e.g., the LEDlighting elements 265) is incident on a top of an LED housing of anadjacent LED lamp and is obstructed or prevented to propagate further.Only a small portion of the light can propagate to enter at an angleinto a top of a scattering part of an adjacent cover unit for theadjacent LED lamp. Moreover, the angle into the top of the scatteringpart of the adjacent cover unit is increased compared to that with thelight blocking part (as shown in FIG. 24). Thus, the light from the LEDlamp 264 entering into the top of the scattering part of the adjacentcover unit can be greatly reduced.

Similar to the scattering part 241 of FIG. 24, the scattering part 261can have a spherical outer surface. An inner surface of the scatteringpart 261 can be an immense extent of the cover unit 260. The innersurface of the scattering part 261 faces away from the spherical outersurface and defines a recess 263 sized based on an upper extent of theLED housing 266 of the underlying LED lamp 264. A depth of the recess263 can be smaller than that of the recess 243 of FIG. 24. The depth canbe within a range of 0.05a˜0.25a, where a is a period of the LED pixelunits. A width of the recess 263 can be slightly larger than a width ofthe LED lamp 264, such that, during installation, the LED housing 266can be positioned within the recess 263 to locate a relative positionbetween the cover unit 260 and the LED lamp 264.

In some implementations, at a cross section of every four adjacent LEDpixel units, a fixing column 268 is installed, as illustrated in FIGS.26B and 26C. FIG. 26B is a cross-sectional view of two adjacent lampcover units 260 without light blocking parts installed with fixingcolumns 268 in another example LED display screen cover, and FIG. 26C isa bottom view of the LED display screen cover of FIG. 26B. Each column268 can be protruded from an intersection of adjacent cover units 260and arranged between four adjacent LED lamps 264. A height of the columncan be a distance from a bottom of the scattering part 261 of the coverunit 260 to the top of the PCB board coupled to the bottom of the LEDbase 264. When installing the LED display screen cover to an array ofunderlying LED pixel units, the columns 268 can be fixed to the PCBboard under the LED bases 267, for example, bottoms of the columns 268can be glued to the top of the PCB board, to fix the LED display screencover.

Compared to the LED display screen cover having cover units with lightblocking parts (as shown in FIG. 24), the LED display screen coverhaving cover units without light blocking parts (as shown in FIGS.26A-26C) is easier to fabricate. As a density of LED pixel units isincreasing, a distance between adjacent LED lamps is decreasingaccordingly, which requires a thinner light blocking part between theadjacent LED lamps. However, due to restrictions in manufacturing orfabricating technologies, it may be difficult to fabricate the thinnerlight blocking part. In comparison, the LED display screen cover havingcover units without light blocking parts does not suffer from therestrictions and can have a higher fabrication accuracy and a betterperformance.

FIG. 27A is a cross-sectional view of an example lamp cover unit 270having a square pyramid structure in another example LED display screencover. FIG. 27B is a schematic diagram of a front side of the LEDdisplay screen cover of FIG. 27A. The cover unit 270 can have aperformance similar to the cover unit 240 or realize functions similarto the cover unit 240.

Similar to the cover unit 240 of FIG. 24, the cover unit 270 includesthe scattering part 271, a light blocking part 272 and a recess 273.Different from the cover unit 240, where the scattering part 241 has aspherical structure with a spherical outer surface, the cover unit 270includes a square pyramid structure as the scattering part 271 and has asquare pyramid outer surface. Corners of an LED lamp 274 under the coverunit 270 in an LED pixel unit are connected to an apex of the squarepyramid structure along sides of the square pyramid structure. In someimplementations, a height H defined by the square pyramid structure (orthe square pyramid outer surface) is within a range of 0.3a˜0.9a, wherea is a period of the LED pixel units.

FIG. 28A is a cross-sectional view of an example lamp cover unit 280having a square frustum structure in another example LED display screencover. FIG. 28B is a schematic diagram of a front side of the LEDdisplay screen cover of FIG. 28A. The cover unit 270 can have aperformance similar to the cover unit 240 or realize functions similarto the cover unit 240.

Similar to the cover unit 240 of FIG. 24, the cover unit 280 includesthe scattering part 281, a light blocking part 282 and a recess 283. Thecover unit 280 is configured to be positioned over an LED lamp 284 in anLED pixel unit. Different from the cover unit 240, where the scatteringpart 241 has a spherical structure with a spherical outer surface, thecover unit 280 includes a square frustum structure as the scatteringpart 281 and has a square frustum outer surface. The square frustumstructure has a flat top surface. An edge length of the top surface ofthe square frustum structure can be within a range of 0.4a˜0.7a, where ais a period of the LED pixel units. A height H defined by the squarefrustum structure (or the square frustum outer surface) is within arange of 0.3a˜0.9a.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention. Forexample, screen covers described here can be also used in liquid crystaldisplays (LCDs) or other image or video display systems. Light sourcesof the display systems can be LED lamps, lasers, semiconductor diodes,or any suitable light sources. Accordingly, other embodiments are withinthe scope of the following claims.

What is claimed is:
 1. A screen cover comprising: a screen cover bodyincluding an array of cover units arranged in multiple rows and multiplecolumns, each cover unit configured to be positioned over a respectiveLED lamp of an array of LED pixel units, wherein each cover unit has ashaped outer surface with edges, including an edge in common with anadjacent cover unit in a same row and an edge in common with an adjacentcover unit in a same column, such that the outer surfaces of the coverunits along the columns and rows together form a continuous outer coversurface, wherein the outer surface of each cover unit has a centralportion elevated above its edges in common with adjacent cover units inthe same column and in the same row, and wherein each cover unit has aninner surface facing away from the shaped outer surface and defining arecess sized based on an upper extent of an LED housing of an underlyingLED lamp.
 2. The screen cover of claim 1, wherein a depth of the recessis within a range of 0.05a˜0.25a, where ‘a’ is a period of the LED pixelunits.
 3. The screen cover of claim 1, wherein the inner surface is animmense extent of the cover unit.
 4. The screen cover of claim 1,wherein the recess has a transitional circular arc between adjacentsides of the recess.
 5. The screen cover of claim 1, wherein the shapedouter surface is configured such that the recess is enclosed by theshaped outer surface.
 6. The screen cover of claim 1, wherein a distancebetween a top of the shaped outer surface and a top of the recess isdetermined based on a shape of the shaped outer surface.
 7. The screencover of claim 1, wherein a distance between a top of the shaped outersurface and a top of the recess is within a range of 0.3˜0.9a, where ‘a’is a period of the LED pixel units.
 8. The screen cover of claim 1,wherein each cover unit comprises a light blocking part configured toblock off light from adjacent LED pixel units.
 9. The screen cover ofclaim 1, wherein the shaped outer surface of the cover unit isspherical.
 10. The screen cover of claim 1, wherein the shaped outersurface of the cover unit comprises a non-spherical surface includingone of ellipsoid, paraboloid, and Bessel surface.
 11. The screen coverof claim 1, wherein the shaped outer surface of the cover unit comprisesa square pyramid surface.
 12. The screen cover of claim 11, wherein aheight defined by the square pyramid surface is within a range of0.3a˜0.9a, where ‘a’ is a period of the LED pixel units.
 13. The screencover of claim 1, wherein the shaped outer surface of the cover unitcomprises a square frustum surface.
 14. The screen cover of claim 13,wherein a height defined by the square frustum surface is within a rangeof 0.3a˜0.9a, and an edge length of a top of the square frustum surfaceis within a range of 0.4a˜0.7a, where ‘a’ is a period of the LED pixelunits.
 15. A covered LED screen, comprising: an array of LED pixel unitsarranged in multiple rows and multiple columns; and a screen cover bodywith an array of LED cover units disposed in multiple rows and multiplecolumns, each cover unit configured to be positioned over an LED lamp ofa respective one of the LED pixel units, wherein each cover unit has ashaped outer surface with edges, including an edge in common with anadjacent cover unit in a same row and an edge in common with an adjacentcover unit in a same column, such that the outer surfaces of the coverunits along the columns and rows together form a continuous outer coversurface, wherein the outer surface of each cover unit has a centralportion elevated above its edges in common with adjacent cover units inthe same column and in the same row, and wherein each cover unit has aninner surface facing away from the shaped outer surface and defining arecess sized based on an upper extent of an LED housing of an underlyingLED lamp.
 16. The covered LED screen of claim 15, wherein each LED pixelunit is enclosed in an LED housing, and sides of the LED housingdirectly face to adjacent sides of LED housings of adjacent LED pixelunits.
 17. The covered LED screen of claim 15, further comprising aplurality of columns each protruded from an intersection of bottoms ofadjacent cover units and arranged between the respective LED pixel unitsunder the adjacent cover units.
 18. The covered LED screen of claim 17,wherein each column extends from the bottoms of the adjacent cover unitsto a printed circuit board (PCB) coupled to bottoms of the LED pixelunits.
 19. The covered LED screen of claim 15, wherein the shaped outersurface of the cover unit has a lowest extent no higher than a lightingelement of an underlying LED lamp.